Cardio-pulmonary by-pass oxygenator unit



Dec. 13, 1966 R. D. SAUTTER CARDIO-PULMONARY BY-PASS OXYGENATOR UNITFiled April 6, 1964 RECIRCULATING VENOUS BLOOD 42 SOURCE LOOD RETURNINVENTOR Richard D. Soufler Luzo 8: Barry OX YGEN SUPPLY AttorneysUnited States Patent O 3,291,568 CARDIO PULMONARY BY-IASS OXYGENATORUNIT Richard D. Sautter, 806 E. 17th St, Marshfield, Wis. Filed Apr. 6,1964, Ser. No. 357,484 7 Ciaims. (Cl. 23-2585) This invention relates toa cardio-pulmonary by-pass unit particularly designed for use in thehypothermic low flow hemodilution technique of total body perfusion.

The idea of oxygenating the circulating blood outside of the body byartifical means is not new and the need for a successful bloodoxygenating heart-lung apparatus has been recognized for many years. Inthe development of such devices oxygenation of the blood by bubblingoxygen through the desaturated venous blood has been found to be quitesuccessful and one of the most practical ways in the point of rate ofoxygenation required for continued recirculation of the blood. Manydevices have been developed to accomplish this result, but have for themost part been impractical for emergency and regular use because of thetime required to set up the unit, complications in autoclaving anddifficulty of disassembly.

One of the primary objects of the present invention is to provide animproved blood oxygenating unit which overcomes the above limitations.

Another object of the present invention is to provide a bloodoxygenating unit that is inexpensive to manufacture and requires littleor no maintenance.

Another object of the present invention is to provide a bloodoxygenating device that can be assembled in a minimum of time.

A further object is to provide a blood oxygenating device that combinesa heat exchanger, blood oxygenator and a reservoir into a singleintegral unit.

A further object of the present invention is to provide a bloodoxygenating unit that is absolutely fail-safe in that it is free ofinternal leaks.

A still further object of this invention is to provide a unit that isreadily adaptable to autoclaving.

A still further object of the present invention is to provide a bloodoxygenating unit that has good heat exchange efiiciency for the surfacearea available.

These objects are accomplished by forcing oxygen under a pressure of 10liters/min. through a perforated disc which disperses the oxygen in theform of minute bubbles as it enters the oxygenating column. Blood isadmitted to the oxygenating column at a point just above the dispersedoxygen so that the oxygen bubbles through the blood as it rises in acenter vertical column. The oxygenated blood is carried from the top ofthe column into a defoaming canister which eliminates the foam in theblood prior to its return to a reservoir which surrounds the centercolumn. A heat exchange jacket is provided between the oxygenatingcolumn and reservoir and also around the defoaming canister throughwhich a heat exchange medium is passed under controlled temperatureconditions. A flat spiral strip is wound around the outer periphery ofthe heat exchange jacket within the reservoir and is connected to thebottom of the defoaming canister by a dependent loop tube which preventsthe admission of air bubbles to the reservoir. The defoamed blood iscarried gently around the outer surface of the heat exchanger by thespiral strip downward to the bottom of the reservoir where it iscollected temporarily prior to its return to the patient. Thetemperature of the heat exchange medium which flows through the heatexchangers is controlled only to the extent necessary to maintain thedesired temperature of the vital organs of the body.

3,2915% Patented Dec. 13, 1966 In cleaning the device, the cap used tohold the perforated disc is quickly removed to expose the interiorsurface of the oxygenating column. The defoaming canister is sealed tothe top of the oxygenating column by tubing which can be lifted off ofthe column to open the column at both ends. The inlet and outlet tubesare removed for autoclaving. The reservoir can be cleaned by removingthe outer plastic wall of the unit to expose the spiral strip. When theassembled oxygenating unit is to be placed in an autoclave, the bloodinlets and outlets are temporarily covered with a qauze which is removedwhen the connections are to be made to the corresponding tubes.

Other objects and advantages will become more readily apparent from thefollowing detailed description when read in connection with theaccompanying drawings, in which:

FIG. 1 is a side view in sectional elevation of the blood oxygenatingapparatus.

FIG. 2 is an exploded view of the lower portion of the oxygenatingapparatus to show the oxygen dispersing system.

FIG. 3 is a view of the dispersion disc.

In the embodiment shown in the drawings, the cardioplumonary by-passunit includes a vertical oxygenating column 10 and a heat exchangejacket 12 both made of a chemically inert material such as stainlesssteel. The jacket is coaxially mounted on the column and silver brazedthereto at 14 and 16 to form a Water tight joint.

The inner surface of the column and the outer surface of the jacket arehighly polished to reduce trauma in the blood.

A flange 18 is secured to the upper end of the water jacket and a flange2%) is secured to the lower end of the jacket. A flat spiral strip 22 isspirally wound around the outer surface of the jacket between theflanges and is silver brazed thereto to form a fluid tight connection. Amayon plastic tubing 24 is slipped over the flanges and sealed theretoby hose clamp 26, 28 to form reservoir 30 around the outer surface ofthe jacket. The plastic tube fits the strip snugly and forms a seal withthe outer edge of the strip so that it acts as a bubble trap.

The lower end of the column is threaded at 32 to receive a cap 34 whichsupports an oxygen inlet and dispersion unit 35. Oxygen which isadmitted to oxygen inlet 36 will be dispersed through perforations 40 inthe disc. Venous blood which is admitted to the column through inlets 42and 44 will be foamed by the dispersed oxygen and will rise in thecolumn. One of the venous blood inlets is connected to receive bloodfrom the cavae or right heart while the other inlet is used for thecardiotomy suction return.

The upper end of the'column is connected to an inlet 46 on a defoamingcanister 48 by means of a mayon plastic tube 50 which is sealed to thecolumn and inlet by hose clamps 52. The foamed blood which rises in thecolumn will overflow into the canister and will pass through a defoamingmaterial such as a silicon coated stainless steel sponge enclosed in afine mesh nylon filter which is located within the canister. A heatexchange jacket 70 is provided around the outside surface of thedefoaming canister. A mayon plastic tube 54 may be connected to anopening 55 in the bottom of the canister and taped to the upper portionof the side of the heat exchange jacket to show the height of bloodwithin the canister.

In the unit presently being used, the oxygenating column isapproximately 21.5 inches long with an internal diameter of 1.180 inchesand an outer diameter of 1.250 inches. The heat exchange jacket is 17.25inches in length with an internal diameter of 1.430 inches and an outerdiameter of 1.50 inches; The reservoir which is formed by the mayonplastic tube is 15.75 inches long with an internal diameter of 2.50inches, thus allowing approximately 1.00 inch between the water jacketand the tubing for the flat spiral strip. The top of the oxygenatingcolumn is connected to the bottom of the defoaming canister by a mayonplastic tube approximately four inches long and having an internaldiameter of one and one-half inches.

The defoamed oxygenated blood from the canister will flow through outlet56 into a mayon plastic tube 58 approximately 24 inches long which islooped at 57 and connected to reservoir inlet tube 60 in flange 18. Thedependent loop acts to prevent any bubbles from entering the reservoirand therefore acts as an additional protection against air embolism. Theoxygenated blood will flow gently down the flat spiral wound strip tothe bottom of the reservoir where it is pumped out through reservoiroutlet tube 62. A vent tube 64 is connected to opening 66 in flange 18and is taped to the side of the canister to compensate for changes inthe pressure in the reservoir.

Water for the water jacket is admitted to the jacket through inlet 68and rises to the top of the jacket where it leaves through outlet 70. Amayon plastic tube 72 is connected between the water jacket outlet andinlet 74 to water jacket 70 on the defoaming canister. The water willrise in the canister jacket to outlet 76 and will then be returned to awater pump for recirculation. The

.water temperature used in the unit is controlled in response to therequirements of the patient. With the water jacket located between theoxygenating column and the reservoir, the temperature of the incomingand outgoing blood can be better controlled.

The oxygen inlet and dispersion unit (FIGS. 2 and 3) has a steel washer78 positioned on the lower end of the vertical oxygenating column, adisc 38 positioned below the steel ring and a rubber O-ring 80positioned below the disc. The washer and disc are held in place by aseat 82 which underlies the disc and has its outer periphery sealed tothe inner surface of the column by the rubber O-ring. Seat 82 has acentral aperture 84 which is aligned with the inlet tube 36 to allow foradmission of oxygen to the space below the disc.

In preparing the unit for autoclaving, the blood outlet, the two bloodinlets and the oxygenator inlet tube are covered with gauze held inplace with masking tape. Autoclaving is then done with the unitcompletely assembled. The gauze is removed just prior to connection ofthe appropriate lines to the connectors. These connections can be madesterilely without the use of gowns or gloves.

The oxygenator is designed for quick setup and is usually stored in anassembled condition; in use, it is merely set up in a vertical positionby any appropriate means. The proper tube connections are made to thevarious tube inlets and outlets and to the proper pumps. Water iscontinuously pumped through the water jacket at a controlled temperatureto bring the apparatus up to operating temperature and maintain it atthat temperature. When the pumps are started after the proper tubeconnections have been made, desaturated venous blood will flow bygravity through the inlet tubes and into the bubbling column. Oxygen issupplied under a pressure of 5-10 liter/min. to the oxygen inlet andwill be dispersed by the disc in the form of small bubbles which aeratethe blood in the column. The bubbling column slowly fills with anuninterrupted rising column of bub bles which are in heat exchangerelation to the heat exchanger until the blood overflows into thedefoaming canister. The defoa-ming material will strip any occludedbubbles from the oxygenated blood as it flows to the bottom of thecanister.

The oxygenated and defoamed blood then flows through the looped tube tothe upper end of the spiral strip which 'carries the blood gentlydownward around the surface of the water jacket. Since the temperatureof the wall of the water jacket is varied according to the requirementsof the patient, the temperature of the blood as it flows into thereservoir will be changed to the desired temperature. A small amount ofoxygenated blood is collected in the reservoir before the return pump isstarted to prevent the possibility of drawing air from the reservoir.The vent tube in the top of the reservoir allows for variations inpressure in the reservoir by the incoming and outgoing blood.

This apparatus can be quickly and easily disassembled for sterilizing bymerely removing all tubing, unscrewing the end cap for the oxygen inletand dispersion unit and removal of the defoaming canister. Theoxygenating column will then be open at both ends and the reservoir andheat exchange jacket will be open at both the inlet and outlet. Becauseof the simplicity in setup and autoclaving of this unit, it has beenfound to be usable both for emergency and general use.

Although only one embodiment of the invention has been shown anddescribed, it should be apparent that various changes and modificationscan be made in this unit without departing from the scope of theappended claims.

What is claimed is:

1. A blood oxygenating unit comprising a chamber having an inlet at thebottom and an outlet at the top,

a heat exchange jacket surrounding said chamber, means for circulating aheat exchange medium through said jacket at a controlled temperature,

means for delivering venous blood to the inlet to said chamber,

means for admitting oxygen into said chamber to force the venous bloodto rise in the chamber,

def-oaming means connected to the outlet of said chamber to defoam theblood as it flows from the chamber,

a flat strip wound spirally around and secured to the outside of saidheat exchanger a removable tubular plastic member mounted on the outeredge of the flat strip to form a reservoir around the outside of saidjacket.

tube means for delivering defoamed blood from the defoaming means to thetop of the spiral strip, and

tube means for removing blood from the bottom of said reservoir asneeded.

2. An oxygenating unit according to claim 1 wherein said means fordelivering defoamed blood to the top of said spiral strip comprises atube looped to prevent the passage of air into said reservoir.

3. An oxygenating unit according to claim 1 wherein said defoaming meansincludes a water jacket surrounding said canister and means fordelivering the heat exchange medium from said heat exchange jacketsurrounding said chamber to the heat exchange jacket surrounding saiddefoaming means.

4. A blood oxygenating device comprising a vertical cylinder open atboth ends,

a cylindrical heat exchange jacket having an inlet and an outletcoaxially mounted on said cylinder and sealed thereto means forcirculating a heat exchange medium through said jacket,

a flat strip spirally wound around said jacket with its inner edgesealed to the outer surface of said jacket,

a plastic tube coaxially mounted on said cylinder in sealed engagementwith the outer edge of said strip to form a reservoir,

an oxygen inlet and dispersion means positioned in the lower open end ofsaid chamber, and

inlet means in said cylinder immediately above said oxygen inlet anddispersion means to admit desaturated blood to said cylinder, defoamingmeans connected to the open upper end of said cylinder, tube meansconnecting the defoaming means to the top of the spiral strip and outletmeans at the bottom of the reservoir to allow oxygenated blood to beremoved from the reservoir.

5 6 5. A blood oxygenating unit according to claim 4 means forcirculating a heat exchange medium through including flange means atboth ends of said spiral strip said second cylinder, and to seal theends of said plastic tube to said Water jacket to tube means forremoving oxygenated blood from the form a reservoir around the outerperiphery of said reservoir. jacket. 5 7. A blood oxygenating unitaccording to claim 6 6. A blood oxygenating unit comprising a firstcylinder wherein said defoaming means includes a dependent loop open atboth ends, tube means for preventing bubbles from entering the a secondcylinder coaxially mounted on said first cylreservoir.

inder and having both ends sealed thereto a spiral strip mounted aboutthe outer surface of said second 10 References Cited y the Examinercylinder to form P3. spiral flow path from the top of UNITED A S PATENTSthe cylinder to the bottom of the reservoir, a third flexible cylindercoaxially mounted on said 2730337 1/1956 Roswell 165156 X Spiral Stripand sealed thereto 2,870,997 1/1959 Soderstrom 165141 dispersion meansfor admitting oxygen to th lower 15 2,934,067 4/1960 Call/1n 128-214 endof said first cylinder, OTHER REFERENCES tube means in close proximityto sa1d dispersion means for admitting venous blood to said firstcylinder, F et Hlgh Output Bubble Oxygenator Wlth defoaming meansconnected to the other end of said Vanable Oxygenafing Chamber forcardiac Bypass cylinder and to said third cylinder for delivering 20Surgery May 19601 772-83 defoamed blood from said first cylinder to saidthird cylinder, said third cylinder forming a reservoir RICHARD GAUDETPnmary Examiner about said second cylinder, DALTON L. TRULUCK, Examiner.

1. A BLOOD OXYGENATING UNIT COMPRISING A CHAMBER HAVING AN INLET AT THEBOTTOM AND AN OUTLET AT THE TOP, A HEAT EXCHANGE JACKET SURROUNDING SAIDCHAMBER, MEANS FOR CIRCULATING A HEAT EXCHANGE MEDIUM THROUGH SAIDJACKET AT A CONTROLLED TEMPERATURE, MEANS FOR DELIVERING VENOUS BLOOD TOTHE INLET TO SAID CHAMBER, MEANS FOR ADMITTING OXYGEN INTO SAID CHAMBERTO FORCE TTHE VENOUS BLOOD TO RISE IN THE CHAMBER, DEFOAMING MEANSCONNECTED TO THE OUTLET OF SAID CHAMBER TO DEFOAM THE BLOOD AS IT FLOWSFROM THE CHAMBER, A FLAT STRIP WOUND SPIRALLY AROUND AND SECURED TO THEOUTSIDE OF SAID HEAT EXCHANGER A REMOVABLE TUBULAR PLASTIC MEMBERMOUNTED ON THE OUTER EDGE OF THE FLAT STRIP TO FORM A RESERVOIR AROUNDTHE OUTSIDE OF SAID JACKET. TUBE MEANS FOR DELIVERING DEFOAMED BLOODFROM THE DEFOAMING MEANS TO THE TOP OF THE SPIRAL STRIP, AND TUBE MEANSFOR REMOVING BLOOD FROM THE BOTTOM OF SAID RESERVOIR AS NEEDED.